Elisa Dominese: 1D contact resistance in encapsulated graphene

Elisa Dominese, Bjarke Sørensen Jessen, Lene Gammelgaard Politecnico di Milano When encapsulated in high-quality hexagonal boron nitride, the carrier mobility of graphene approach the theoretical maximum predicted for clean, disorder-free graphene having zero interaction with the surroundings [1]. A surprisingly efficient way to form electrical contact to the buried graphene layer is by a metallic contact to the exposed, one-dimensional graphene edge at the fringe of the heterostructure. The contact resistance is still a bottleneck for many device applications including field effect transistors based on graphene. In this work we study the role of the geometry, size and position of the electrical edge contacts on the gate-voltage dependent contact resistance. An SF6 based etching recipe and the use of thermally controlled heterostructure assembly [2], allows a high degree of control in creating the device and defining the edges.  Inspired by the recently discovered angular dependence of interlayer contact resistance [3] we also study the possibility of angular dependence of edge contacts with respect to the graphene lattice orientation. 1. L. Wang et al., One-Dimensional Electrical Contact to a Two-Dimensional Material. Science 342, 614-617 (2013) 2. F. Pizzocchero et al., The hot pick-up technique for batch assembly of van der Waals heterostructures. Nature Communications 7 (2016) 3. T. Chari et al., Resistivity of Rotated Graphite–Graphene Contacts. Nano Letters 16, 4477-4482 (2016) Elisa Dominese studies Materials Engineering and Nanotechnology at Politecnico di Milano. She decided to complete her course of study doing the master thesis project abroad joining the Nanocarbon group directed by professor Peter Bøggild at DTU Nanotech.